1. Field of the Invention
The present invention relates to a data read/write device and method using a recording medium such as a high-density optical disc.
2. Description of the Related Art
There has been a need to manage optical disc media in a highly reliable manner in order to increase their recording density. In this connection, defect management information, stored on each loaded disc to indicate the defect locations and the corresponding spare areas on the disc, is essential to data read/write operation. Further, in order to allow a setup operation to be efficiently performed on the device, the disc stores information about the various conditions under which data was previously written to or read from it (e.g., the magnitude of the write power) and this information is later read at the beginning of each subsequent read or write operation. The defect management information is redundantly stored in a plurality of disc management areas (hereinafter referred to as DMAs) on the disc.
For example, a DVD-RAM disc has four disc management areas (DMA 1 to DMA 4) thereon; two of them are provided-on the inner circumferential side of the optical disc and the other two are provided on the outer circumferential side (see, e.g., Japanese Patent Laid-Open No. 2002-245723).
Further, in the case of a DVR (Data & Video Recording) disc (a high-capacity high-density disc), the two disc management areas (DMA 1 and DMA 2) on the inner circumferential side are radially spaced apart from each other by a test write area (OPC). This arrangement prevents both disc management areas (DMA 1 and DMA 2) from being damaged at once due to a defect, flaw, etc., thereby increasing the reliability of these DMAs. The disc definition structure (DDS) stored in each disc management area holds the update count, and if the count has reached its maximum value of overwrite count, another disc management area is used to store defect management information, thereby increasing the reliability of the read/write operation on the DMAs. Further, with this arrangement, the update counts held in the DDSs are compared with one another to determine which one or ones of the DMAs store valid data (see, e.g., Japanese Patent Laid-Open No. 2004-14088).